Prohibition - Oversimplified
https://www.youtube.com/watch?v=AAGIi62-sAU&t=21s
BU:GU= .5; neither malty nor hoppy; balanced
"...IBUs dropped from a pre-Prohibition level of 30–40 to 25–30 after Prohibition." - BJCP So, if you prefer to have a more authentic version of the pre-prohibition lager, then up the cluster hops to 46 grams for 30 minutes of the boil.
Carapils did not exist prior to U.S. prohibition laws, so it is not an authentic addition. It is included to increase head retention. For a more authentic pre-prohibition style, remove the Carapils malt from the recipe and brew with the same amounts of all other ingredients. This will adjust the alcohol content and IBU, but only a small amount.
Whirlfloc tablets did not exist prior to U.S. prohibition laws, so they are not an authentic addition. They are added to clarify the beer. The method to clear the beer of the high residual proteins from the 6-row malt that is used in this recipe would have been to include a protein rest.
https://www.midwestsupplies.com/blogs/bottled-knowledge/what-is-a-protein-rest-when-do-i-need-to-use-it
Whirlpool